This invention relates generally to can filling apparatus and methods applicable to the handling of wet food materials, such as blanched spinach. It relates to apparatus and methods for automatically controlling to such apparatus feeding of material.
In my copending application Ser. No. 669,327, filed Mar. 22, 1976 now U.S. Pat. No. 4,019,547 date Apr. 26, 1977 and entitled "Can Filling Method and Apparatus", there is disclosed an apparatus and method which is applicable for filling cans with wet food material, like blanched spinach, with a high degree of accuracy with respect with the weight of material supplied to each can. The apparatus in that instance makes use of an upright tube open at its upper end to receive the wet material, and having means at its lower end to successively cut off equal volumes of the material for introduction into underlying cans. The upper open end of the tube communicates with a hopper, and feed means delivers the material to a region from which it is dropped into the hopper. Said copending application Ser. No. 782,924, now U.S. Pat. No. 4,122,875 of which this application is a division, discloses improved means for feeding the wet material to the upright tube.
For the purpose of automatically maintaining a column of material of constant height in the tube of the can filling assembly, pneumatic sensors are disclosed in said patent, which function to shut off the drive to the conveyer of the feed means when the column of material exceeds a predetermined height. It has been found that this type of control is not as sensitive or reliable as desired, which is attributed in part to condensation of moisture in the small passages or orifices through which air is discharged into one side of the vertical tube. In addition, such a sensing arrangement requires use of a tube sufficiently long to provide an extension at its upper end where the sensing devices are located.